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   1 /*
   2  *  linux/net/sunrpc/gss_krb5_crypto.c
   3  *
   4  *  Copyright (c) 2000 The Regents of the University of Michigan.
   5  *  All rights reserved.
   6  *
   7  *  Andy Adamson   <andros@umich.edu>
   8  *  Bruce Fields   <bfields@umich.edu>
   9  */
  10
  11 /*
  12  * Copyright (C) 1998 by the FundsXpress, INC.
  13  *
  14  * All rights reserved.
  15  *
  16  * Export of this software from the United States of America may require
  17  * a specific license from the United States Government.  It is the
  18  * responsibility of any person or organization contemplating export to
  19  * obtain such a license before exporting.
  20  *
  21  * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
  22  * distribute this software and its documentation for any purpose and
  23  * without fee is hereby granted, provided that the above copyright
  24  * notice appear in all copies and that both that copyright notice and
  25  * this permission notice appear in supporting documentation, and that
  26  * the name of FundsXpress. not be used in advertising or publicity pertaining
  27  * to distribution of the software without specific, written prior
  28  * permission.  FundsXpress makes no representations about the suitability of
  29  * this software for any purpose.  It is provided "as is" without express
  30  * or implied warranty.
  31  *
  32  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  33  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  34  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  35  */
  36
  37 #include <linux/types.h>
  38 #include <linux/mm.h>
  39 #include <linux/slab.h>
  40 #include <asm/scatterlist.h>
  41 #include <linux/crypto.h>
  42 #include <linux/highmem.h>
  43 #include <linux/pagemap.h>
  44 #include <linux/sunrpc/gss_krb5.h>
  45
  46 #ifdef RPC_DEBUG
  47 # define RPCDBG_FACILITY        RPCDBG_AUTH
  48 #endif
  49
  50 u32
  51 krb5_encrypt(
  52         struct crypto_tfm *tfm,
  53         void * iv,
  54         void * in,
  55         void * out,
  56         int length)
  57 {
  58         u32 ret = -EINVAL;
  59         struct scatterlist sg[1];
  60         u8 local_iv[16] = {0};
  61
  62         dprintk("RPC:      krb5_encrypt: input data:\n");
  63         print_hexl((u32 *)in, length, 0);
  64
  65         if (length % crypto_tfm_alg_blocksize(tfm) != 0)
  66                 goto out;
  67
  68         if (crypto_tfm_alg_ivsize(tfm) > 16) {
  69                 dprintk("RPC:      gss_k5encrypt: tfm iv size to large %d\n",
  70                          crypto_tfm_alg_ivsize(tfm));
  71                 goto out;
  72         }
  73
  74         if (iv)
  75                 memcpy(local_iv, iv, crypto_tfm_alg_ivsize(tfm));
  76
  77         memcpy(out, in, length);
  78         sg[0].page = virt_to_page(out);
  79         sg[0].offset = offset_in_page(out);
  80         sg[0].length = length;
  81
  82         ret = crypto_cipher_encrypt_iv(tfm, sg, sg, length, local_iv);
  83
  84         dprintk("RPC:      krb5_encrypt: output data:\n");
  85         print_hexl((u32 *)out, length, 0);
  86 out:
  87         dprintk("RPC:      krb5_encrypt returns %d\n",ret);
  88         return(ret);
  89 }
  90
  91 EXPORT_SYMBOL(krb5_encrypt);
  92
  93 u32
  94 krb5_decrypt(
  95      struct crypto_tfm *tfm,
  96      void * iv,
  97      void * in,
  98      void * out,
  99      int length)
 100 {
 101         u32 ret = -EINVAL;
 102         struct scatterlist sg[1];
 103         u8 local_iv[16] = {0};
 104
 105         dprintk("RPC:      krb5_decrypt: input data:\n");
 106         print_hexl((u32 *)in, length, 0);
 107
 108         if (length % crypto_tfm_alg_blocksize(tfm) != 0)
 109                 goto out;
 110
 111         if (crypto_tfm_alg_ivsize(tfm) > 16) {
 112                 dprintk("RPC:      gss_k5decrypt: tfm iv size to large %d\n",
 113                         crypto_tfm_alg_ivsize(tfm));
 114                 goto out;
 115         }
 116         if (iv)
 117                 memcpy(local_iv,iv, crypto_tfm_alg_ivsize(tfm));
 118
 119         memcpy(out, in, length);
 120         sg[0].page = virt_to_page(out);
 121         sg[0].offset = offset_in_page(out);
 122         sg[0].length = length;
 123
 124         ret = crypto_cipher_decrypt_iv(tfm, sg, sg, length, local_iv);
 125
 126         dprintk("RPC:      krb5_decrypt: output_data:\n");
 127         print_hexl((u32 *)out, length, 0);
 128 out:
 129         dprintk("RPC:      gss_k5decrypt returns %d\n",ret);
 130         return(ret);
 131 }
 132
 133 EXPORT_SYMBOL(krb5_decrypt);
 134
 135 static void
 136 buf_to_sg(struct scatterlist *sg, char *ptr, int len) {
 137         sg->page = virt_to_page(ptr);
 138         sg->offset = offset_in_page(ptr);
 139         sg->length = len;
 140 }
 141
 142 static int
 143 process_xdr_buf(struct xdr_buf *buf, int offset, int len,
 144                 int (*actor)(struct scatterlist *, void *), void *data)
 145 {
 146         int i, page_len, thislen, page_offset, ret = 0;
 147         struct scatterlist      sg[1];
 148
 149         if (offset >= buf->head[0].iov_len) {
 150                 offset -= buf->head[0].iov_len;
 151         } else {
 152                 thislen = buf->head[0].iov_len - offset;
 153                 if (thislen > len)
 154                         thislen = len;
 155                 buf_to_sg(sg, buf->head[0].iov_base + offset, thislen);
 156                 ret = actor(sg, data);
 157                 if (ret)
 158                         goto out;
 159                 offset = 0;
 160                 len -= thislen;
 161         }
 162         if (len == 0)
 163                 goto out;
 164
 165         if (offset >= buf->page_len) {
 166                 offset -= buf->page_len;
 167         } else {
 168                 page_len = buf->page_len - offset;
 169                 if (page_len > len)
 170                         page_len = len;
 171                 len -= page_len;
 172                 page_offset = (offset + buf->page_base) & (PAGE_CACHE_SIZE - 1);
 173                 i = (offset + buf->page_base) >> PAGE_CACHE_SHIFT;
 174                 thislen = PAGE_CACHE_SIZE - page_offset;
 175                 do {
 176                         if (thislen > page_len)
 177                                 thislen = page_len;
 178                         sg->page = buf->pages[i];
 179                         sg->offset = page_offset;
 180                         sg->length = thislen;
 181                         ret = actor(sg, data);
 182                         if (ret)
 183                                 goto out;
 184                         page_len -= thislen;
 185                         i++;
 186                         page_offset = 0;
 187                         thislen = PAGE_CACHE_SIZE;
 188                 } while (page_len != 0);
 189                 offset = 0;
 190         }
 191         if (len == 0)
 192                 goto out;
 193
 194         if (offset < buf->tail[0].iov_len) {
 195                 thislen = buf->tail[0].iov_len - offset;
 196                 if (thislen > len)
 197                         thislen = len;
 198                 buf_to_sg(sg, buf->tail[0].iov_base + offset, thislen);
 199                 ret = actor(sg, data);
 200                 len -= thislen;
 201         }
 202         if (len != 0)
 203                 ret = -EINVAL;
 204 out:
 205         return ret;
 206 }
 207
 208 static int
 209 checksummer(struct scatterlist *sg, void *data)
 210 {
 211         struct crypto_tfm *tfm = (struct crypto_tfm *)data;
 212
 213         crypto_digest_update(tfm, sg, 1);
 214
 215         return 0;
 216 }
 217
 218 /* checksum the plaintext data and hdrlen bytes of the token header */
 219 s32
 220 make_checksum(s32 cksumtype, char *header, int hdrlen, struct xdr_buf *body,
 221                    int body_offset, struct xdr_netobj *cksum)
 222 {
 223         char                            *cksumname;
 224         struct crypto_tfm               *tfm = NULL; /* XXX add to ctx? */
 225         struct scatterlist              sg[1];
 226         u32                             code = GSS_S_FAILURE;
 227
 228         switch (cksumtype) {
 229                 case CKSUMTYPE_RSA_MD5:
 230                         cksumname = "md5";
 231                         break;
 232                 default:
 233                         dprintk("RPC:      krb5_make_checksum:"
 234                                 " unsupported checksum %d", cksumtype);
 235                         goto out;
 236         }
 237         if (!(tfm = crypto_alloc_tfm(cksumname, CRYPTO_TFM_REQ_MAY_SLEEP)))
 238                 goto out;
 239         cksum->len = crypto_tfm_alg_digestsize(tfm);
 240         if ((cksum->data = kmalloc(cksum->len, GFP_KERNEL)) == NULL)
 241                 goto out;
 242
 243         crypto_digest_init(tfm);
 244         buf_to_sg(sg, header, hdrlen);
 245         crypto_digest_update(tfm, sg, 1);
 246         process_xdr_buf(body, body_offset, body->len - body_offset,
 247                         checksummer, tfm);
 248         crypto_digest_final(tfm, cksum->data);
 249         code = 0;
 250 out:
 251         crypto_free_tfm(tfm);
 252         return code;
 253 }
 254
 255 EXPORT_SYMBOL(make_checksum);
 256
 257 struct encryptor_desc {
 258         u8 iv[8]; /* XXX hard-coded blocksize */
 259         struct crypto_tfm *tfm;
 260         int pos;
 261         struct xdr_buf *outbuf;
 262         struct page **pages;
 263         struct scatterlist infrags[4];
 264         struct scatterlist outfrags[4];
 265         int fragno;
 266         int fraglen;
 267 };
 268
 269 static int
 270 encryptor(struct scatterlist *sg, void *data)
 271 {
 272         struct encryptor_desc *desc = data;
 273         struct xdr_buf *outbuf = desc->outbuf;
 274         struct page *in_page;
 275         int thislen = desc->fraglen + sg->length;
 276         int fraglen, ret;
 277         int page_pos;
 278
 279         /* Worst case is 4 fragments: head, end of page 1, start
 280          * of page 2, tail.  Anything more is a bug. */
 281         BUG_ON(desc->fragno > 3);
 282         desc->infrags[desc->fragno] = *sg;
 283         desc->outfrags[desc->fragno] = *sg;
 284
 285         page_pos = desc->pos - outbuf->head[0].iov_len;
 286         if (page_pos >= 0 && page_pos < outbuf->page_len) {
 287                 /* pages are not in place: */
 288                 int i = (page_pos + outbuf->page_base) >> PAGE_CACHE_SHIFT;
 289                 in_page = desc->pages[i];
 290         } else {
 291                 in_page = sg->page;
 292         }
 293         desc->infrags[desc->fragno].page = in_page;
 294         desc->fragno++;
 295         desc->fraglen += sg->length;
 296         desc->pos += sg->length;
 297
 298         fraglen = thislen & 7; /* XXX hardcoded blocksize */
 299         thislen -= fraglen;
 300
 301         if (thislen == 0)
 302                 return 0;
 303
 304         ret = crypto_cipher_encrypt_iv(desc->tfm, desc->outfrags, desc->infrags,
 305                                         thislen, desc->iv);
 306         if (ret)
 307                 return ret;
 308         if (fraglen) {
 309                 desc->outfrags[0].page = sg->page;
 310                 desc->outfrags[0].offset = sg->offset + sg->length - fraglen;
 311                 desc->outfrags[0].length = fraglen;
 312                 desc->infrags[0] = desc->outfrags[0];
 313                 desc->infrags[0].page = in_page;
 314                 desc->fragno = 1;
 315                 desc->fraglen = fraglen;
 316         } else {
 317                 desc->fragno = 0;
 318                 desc->fraglen = 0;
 319         }
 320         return 0;
 321 }
 322
 323 int
 324 gss_encrypt_xdr_buf(struct crypto_tfm *tfm, struct xdr_buf *buf, int offset,
 325                 struct page **pages)
 326 {
 327         int ret;
 328         struct encryptor_desc desc;
 329
 330         BUG_ON((buf->len - offset) % crypto_tfm_alg_blocksize(tfm) != 0);
 331
 332         memset(desc.iv, 0, sizeof(desc.iv));
 333         desc.tfm = tfm;
 334         desc.pos = offset;
 335         desc.outbuf = buf;
 336         desc.pages = pages;
 337         desc.fragno = 0;
 338         desc.fraglen = 0;
 339
 340         ret = process_xdr_buf(buf, offset, buf->len - offset, encryptor, &desc);
 341         return ret;
 342 }
 343
 344 EXPORT_SYMBOL(gss_encrypt_xdr_buf);
 345
 346 struct decryptor_desc {
 347         u8 iv[8]; /* XXX hard-coded blocksize */
 348         struct crypto_tfm *tfm;
 349         struct scatterlist frags[4];
 350         int fragno;
 351         int fraglen;
 352 };
 353
 354 static int
 355 decryptor(struct scatterlist *sg, void *data)
 356 {
 357         struct decryptor_desc *desc = data;
 358         int thislen = desc->fraglen + sg->length;
 359         int fraglen, ret;
 360
 361         /* Worst case is 4 fragments: head, end of page 1, start
 362          * of page 2, tail.  Anything more is a bug. */
 363         BUG_ON(desc->fragno > 3);
 364         desc->frags[desc->fragno] = *sg;
 365         desc->fragno++;
 366         desc->fraglen += sg->length;
 367
 368         fraglen = thislen & 7; /* XXX hardcoded blocksize */
 369         thislen -= fraglen;
 370
 371         if (thislen == 0)
 372                 return 0;
 373
 374         ret = crypto_cipher_decrypt_iv(desc->tfm, desc->frags, desc->frags,
 375                                         thislen, desc->iv);
 376         if (ret)
 377                 return ret;
 378         if (fraglen) {
 379                 desc->frags[0].page = sg->page;
 380                 desc->frags[0].offset = sg->offset + sg->length - fraglen;
 381                 desc->frags[0].length = fraglen;
 382                 desc->fragno = 1;
 383                 desc->fraglen = fraglen;
 384         } else {
 385                 desc->fragno = 0;
 386                 desc->fraglen = 0;
 387         }
 388         return 0;
 389 }
 390
 391 int
 392 gss_decrypt_xdr_buf(struct crypto_tfm *tfm, struct xdr_buf *buf, int offset)
 393 {
 394         struct decryptor_desc desc;
 395
 396         /* XXXJBF: */
 397         BUG_ON((buf->len - offset) % crypto_tfm_alg_blocksize(tfm) != 0);
 398
 399         memset(desc.iv, 0, sizeof(desc.iv));
 400         desc.tfm = tfm;
 401         desc.fragno = 0;
 402         desc.fraglen = 0;
 403         return process_xdr_buf(buf, offset, buf->len - offset, decryptor, &desc);
 404 }
 405
 406 EXPORT_SYMBOL(gss_decrypt_xdr_buf);